Radio‐echo layering in West Antarctica: a spreadsheet dataset     

Martin J. Siegert  Magdeline Pokar  Julian A. Dowdeswell  Toby Benham 《地球表面变化过程与地形》2005,30(12):1583-1591

Of the various information recovered from radio‐echo sounding (RES) of polar ice sheets, internal layering is currently under‐utilized by glaciologists, due in part to a lack of available data. Here, RES layering of the West Antarctic Ice Sheet, from the 1970s RES survey of approximately 70 per cent of this ice mass, is made available in a series of spreadsheets. Three types of internal layers are evident in the dataset. The first is continuous layers that have a stratigraphic appearance and can often be traced easily for hundreds of kilometres. The second is buckled layering, which also resembles stratigraphy and can sometimes be traced over tens of kilometres (although layer identification can often be difficult). The roughness of these layers is often greater than the bed at the same wavelength. The third is highly distorted or absent layering, which is not possible to trace laterally. Despite debate concerning the origin of RES layers, they are thought by most glaciologists to represent isochronous surfaces. The pattern of internal layering is potentially of importance to glaciologists for three reasons. (1) The position of undeformed layers below the ice surface is a function of accumulation rate, ice flow and basal melting conditions. Numerical modelling (including new ‘data assimilation’ techniques) could be used to discriminate between these processes, so revealing important information about the ice sheet and its environment. (2) Buckled layers are deformed by ice flow process, and so their occurrence can be related to the flow dynamics of the ice sheet. (3) Very buckled layers are often associated with ice stream flow, which allows their location to mark the positions of past and present fast‐flowing ice. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献